Production of glucose from starch.



H. WULKAN.

PRODUCTION OF GLUCOSE FROM STARCH'.

APPLICATION FILED Nov. 1, 1912.

1 ,139,620. Pate nted May18,1915.

. INVENTOR e 1zric Wazia'n WI TNESSES;

% A TTOR/VEY cose from Starch, of which the following is an sraras.naranr orrron.

HEINRICH WULKAN, OF BUDAPEST, AUSTRIA-HUNGARY, ASSIGNOR T DEXTRINAUTOMAT, GESELLSCHAFT M. B. H., 0F VIENNA, AUSTRIA-HUNGARY, A CORPO-RATION OF AUSTRIA-HUNGARY.

JEROTD'UCTION OF GLUCOSE FROM STARCH.

A Specification of Letters Patent.

Patented May 18, 1915.

Application filed November 7, 1912. Serial No. 730,071.

a citizen of the Empire of Austria-Hungary,

residing at Budapest, in the Empire of Austria-Hungary, have invented anew and useful Improvement in the Production of Glua specification.

This invention relates to the production of concentrated solutions ofglucose from starch; and it comprises a process in which diluteinversion solutions are used to convert further quantities of starchinto glucose, so that a more concentrated solution is obtained by theuse of the same amount of acid and without further concentration;-

all as more fully hereinafter set forth and as claimed.

In the production of glucose, dextrose, etc, from starch, when thestarch paste is boiled with dilute mineral acids such as sulfuric acidor hydrochloric acid there results a comparatively dilute solutioncontaining only about 25 to 27 per cent. of dry substance; and in orderto obtain a more concentrated solution from this dilute solutionaccording to the processes heretofore practised, evaporation must beresorted to. Such concentrated solutions have heretofore also been madeby the addition of water to the finished commercial articles, but suchpreparation of concentrated goods naturally requires previousconcentration of the original dilute solutions. 1

If sulfuric acid is used for the inversion and calcium carbonate forneutralizing the acid after inversion, calcium sulfate is formed.Calcium sulfate is appreciably soluble in dilute solutions and moresoluble in dilute solutions than in concentrated ones. The partialremoval of this calcium sulfate in the bone black filter necessitates amore frequent renewal of the bone black used for clarifying thesolutions than would otherwise be necessary; and the separating of thedissolved calcium sulfate upon concentration of the'dilute solutionscauses a deposit of this substance in the pipes and coils of the sapparatus with resulting difliculty and expense in its renewal.

According to the novel process of the present invention concentratedsolutions are present invention.

obtained without the necessity of evaporatlng a more dilute solution.According to this process the dilute solution resulting from theinversion of the starch by dilute acid is used to convert a furtherportion of the starch into the glucose, dextrose, etc,

so that as the result a more concentrated solution is obtained; and theconcentration can thus be increased until a solution of sufficientconcentration is obtained. It has been found that the dilute acidinversion solution is still capable of hydroliz'ing new quantities ofstarch and that the same solution can be used repeatedly for thispurpose with resulting increase in concentration and in percentage ofthe inverted product. In the use of the dilute inversion solution fortreating fresh quantities of starch, it is first cooled below thetemperature of gelatinization of the starch before'intermixing it withthe fresh quantities of the starch,

the conversion of the added starch being effected by subsequent heatingafter intermixture with the cooled inversion solution.

The so-called dilute acid inversion solution may be such a solution asresults from the treatment of starch with. dilute acid according toprocesses in which a dilute inversion solution is produced; or it may bea more concentrated solution resulting from an intermediate stage 'ofthe process of the When used repeatedly according to this process itgradually increases in strength until a solution of the desiredconcentration is obtained, the solutions more dilutethan the finalconcentrated solution being as already indicated, capable of convertingfresh quantities of starch into glucose. A further small amount of acidmay be added to the dilute inversion solution. In such case there isobtained a slightlygreater amount of acid in the concentrated solutionsbut with the very small amounts added this increase in concentration ofthe acid does not injuriously affect the product while it neverthelessfacilitates the reaction.

After a solution of the desired or required concentration is obtained.as already described, the solution can be neutralized by the additionof an alkaline or alkaline earth carbonate, or other suitableneutralizing agent. If the neutralization is effected in an open vesselcarbonates such as sodium or calcium carbonate can be used. Afterneutralization the solutions which are already concentrated are at onceavailable for use as concentrated solutions without furtherconcentration. In case it is desired to neutralize the acid in the samevessel in which conversion is efiected or in a closed circulation systemcarbonates cannot be used;

but it has been found that in such cases borax may bejused withadvantageous results. Thus for instance the solution of borax isintroduced in amount sufiicient for complete neutralization, but aslight excess of borax may be used without imparting any injurious colorto the solution.

An apparatus in which the process of the present invention can becarried out is illustrated in the accompanying drawings.

The apparatus here illustrated comprises a closed vessel divided by thehollow part1- tion 0 into an upper chamber A provided with stirringmeans and a lower chamber B in which the conversion of the starch takesplace. The chamber A is the stirring vessel for mixing the starch withthe dilute acid, which mixture may be admitted to the conversion chamberB through the valve g. The partition 0 is shown in the form of a doublewall forming an intervening space in which air or water can becirculated to prevent heating of the starch mixture in A by theinversion mixture in B. The lower chamber B is provided with a steam orliquid inlet valve a, a steam outlet valve 7, a safety valve (notshown), and air valve 0, a pressure gage d, starch mixture inlet 9,outlet 72., and sample cock I). It is also provided with a funnel inletE provided with two stop cocks and with coils D which may be used eitheras a heating means for the inversion solution or a cooling means forcooling the dilute inversion liquor before adding further quantities offresh starch. The valve a can also be used for adding a further amountof dilute liquor or of a mixture of starch and acid to the conversionchamber B at the beginning of the process or at some intermediate stage.The upper chamber A is also provided with an inlet (not shown) foradmission ofthe liquid starch mixture. At the bottom of the chamber B ati the dilute acid inversion liquid may be raised to the top of thechamber A, where it can be mixed with a further quantity of starchandreturned to the chamber B for the next stage of the reaction. In caseborax is used for neutralizing the acid in the apparatus a solution ofit can be introduced by means of the funnel E which is shown as providedwith two' stop cocks, so that the solution can be introduced even whenthe interior of the chamber B is under pressure. In this way the acidcan be neutralized directly in the same vessel in which the acidinversion liquid is produced sov that a neutralized and concentratedsolution can be drawn oil at the bottom of the vessel for further usedirectly without either concentration or neutralization. The acid canhowever be neutralized in a separate receptacle by means of a carbonatesuch as sodium or calcium carbonate but owing to the evolution of carbondioxid an open vessel must be used or one in which provision is made forthe escape of this gas. The use of borax however can take place in aclosed vessel and as already stated in the same vessel in which theconcentrated solution is obtained.

I claim:

1. The process of producing directly concentrated solutions of glucosewhich comprises treating starch with dilute acid to produce a diluteinversion solution, and

, treating fresh quantities of starch with such dilute solution toproduce a more concentrated solution of glucose, whereby a concentratedsolution of glucose is produced directly without evaporation.

2. The process of producing directly concentrated solutions of glucosewhich com-V prises treating starch with dilute acid to produce a diluteinversion solution, and treating fresh quantities of starch containing asmall amount of acid with such dilute solution to produce a moreconcentrated solution of glucose, whereby a concentrated solution ofglucose is produced directly without evaporation.

3. The process of producing concentrated inversion solutions whichcomprises reacting with a dilute acid inversion solution on freshquantities of starch whereby a more concentrated inversion solution isobtained and reacting with the resulting inversion solution on a furtherquantity of fresh starch to produce a more concentrated inversionsolution.

4. The process of producing concentrated inversion solutions whichcomprises reacting repeatedly with a dilute inversion solution uponfresh quantities of starch to produce a solution of gradually increasingconwhich comprises neutralizing the concen- In testimony whereof I havehereunto set trated acid inversion solution by means of my hand in thepresence of two subscribing borex. witnesses.

7. In the production of inversion solutions HEINRICH WULKAN. 5 the stepWhich comprises neutralizing en Witnesses:

acid inversion solution of glucose with GUSTAV LEDERER, borax. ADA MARIABERGER.

